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Overview of New Donor Heart Allocation Tiers
Dan M. Meyer, MDUniversity of Texas Southwestern
Dallas, Texas
© 2016 AST
The Heart Subcommittee was asked by the UNOS Board to explore opportunities for broader, more equitable sharing of donor hearts.
Review requested because of
1) the increase of candidates waiting without a corresponding increase in available donors
2) higher than desirable waiting list mortality rates in higher status patients and
3) changing management of heart failure patients with the increased use of VADs.
Background
© 2016 AST
Goals
• Reduce waiting list mortality rates
• Reduce the use of exceptions by better
accommodating all candidates within the system
• Ensure that qualifying criteria for the statuses
are based on objective physiological indications
rather than therapeutic intervention
• Improve overall access to transplantation by
modifying geographic distribution to ensure
maximum utilization of donor hearts
© 2016 AST
Modify current 3-tiered system
Develop heart allocation score
Add more tiers
Options Considered
5
© 2016 AST
Identify patients with high waitlist mortality
• Considerations: waitlist mortality, transplant rates and post-transplant survival
Define “criteria” for subjective decisions based upon objective data elements and physiological principles
Explore options for broader sharing for the sickest patients
Integrate pediatric allocation
Model the above and hope/pray that the data is interpretable, accurate and explainable
How was the proposal developed?
6
© 2016 AST
0% 2% 4% 6% 8% 10% 12%
WL
Post-TX
Status 2
Status 1B
Status 1A
ALL
% died within 6 months: medical urgency status at listing/transplant
UNOS Data, 2013
© 2016 AST
ALL
ALL
Status 1A-ALL
Status 1A-ALL
Status 1A-(A)
Status 1A-(A)
Status 1A-(B)
Status 1A-(B)
Status 1A-(C)
Status 1A-(C)
Status 1A-(D)
Status 1A-(D)
Status 1A-(E)
Status 1A-(E)
Status 1B
Status 1B
Status 2
Status 2
0% 3% 6% 9% 12% 15% 18%
WL
Post-TXStatus 2
Status 1B
Status 1A-(E)
Status 1A-(D)
Status 1A-(C)
Status 1A-(B)
Status 1A-(A)
Status 1A-ALL
ALL
% died within 6 months*: ever
waiting in criteria
A = Mechanical circulatory support (i.e., VAD for 30 days, TAH, balloon pump, ECMO)
B = Mechanical circulatory support with device complications
C = Mechanical ventilationD = Continuous infusion of single high dose or multiple inotropes + continuous hemodynamic monitoring
E = Exception
Criteria:
* For WL analysis, time is computed from first entry into criteria, rather than time since listing.
UNOS Data, 2013
© 2016 AST
ALL
ALL
Status 1A-ALL
Status 1A-ALL
Status 1A-(A)
Status 1A-(A)
Status 1A-(A)(ii)
Status 1A-(A)(ii)
Status 1A-(A)(iii)
Status 1A-(A)(iii)
Status 1A-(A)(iv)
Status 1A-(A)(iv)
Status 1A-(B)
Status 1A-(B)
Status 1A-(B)(iv)
Status 1A-(B)(iv)
Status 1A-(C)
Status 1A-(C)
Status 1A-(D)
Status 1A-(D)
Status 1A-(E)
Status 1A-(E)
Status 1B
Status 1B
Status 2
Status 2
0% 5% 10% 15% 20% 25% 30% 35%
WL
Post-TX
Status 2
Status 1B
Status 1A-(E)
Status 1A-(D)
Status 1A-(C)
Status 1A-(B)(v)
Status 1A-(B)(iv)
Status 1A-(B)(iii)
Status 1A-(B)(ii)
Status 1A-(B)(i)
Status 1A-(B)
Status 1A-(A)(iv)
Status 1A-(A)(iii)
Status 1A-(A)(ii)
Status 1A-(A)(i)
Status 1A-(A)
Status 1A-ALL
ALL
% died within 6 months*: ever waiting in criteria or
sub-criteria
A(i) =VAD for 30 days B(i) = ThromboembolismA(ii) = TAH B(ii) = Device infectionA(iii) = Intra-aortic balloon pump B(iii) = Device malfunctionA(iv) = ECMO B(iv) = Life-threatening ventricular arrhythmia
B(v) = Other device related complication
Sub-criteria:
* For WL analysis, time is computed from first entry into criteria/sub-criteria, rather than time since listing.
UNOS Data, 2013
© 2016 AST
Categories for adult status 1A exception
•No PAC access, 11%
•VAD complications,
•13% •Hypertrophic CM, 3%
•PAC inappropriate, 7%
•Other: Miscellaneous,
•3% •Retransplant, 13%
•Other, 15% •CAD refractory angina,
•2% •CAD
complications/limited
options, 2%
•HI TX, 2%
•Congenital, 18%
•Restrictive CM, 2%
•Unable to tolerate
•VT/VF, 21% •inotropes, 1%
Am J Transplantation 2015; 15: 44–54
© 2016 AST
Proposed Statuses 1-3
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Status Criteria
1
• ECMO• Continuous Mechanical ventilation• Non-dischargeable (surgically implanted) VAD• MCSD with life-threatening ventricular arrhythmia
2
• Intra-aortic balloon pump• Ventricular tachycardia/ventricular fibrillation, mechanical support not required• MCSD with device malfunction/mechanical failure• Total artificial heart• Dischargeable BiVAD or RVAD• Acute circulatory support
3
• Dischargeable LVAD for up to 30 days• Multiple inotropes or single high-dose inotropes with continuous hemodynamic monitoring• MCSD with device infection• MCSD with hemolysis• MCSD with pump thrombosis• MCSD with right heart failure• MCSD with mucosal bleeding• MCSD with aortic insufficiency
© 2016 AST
Proposed Statuses 4-6
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Status Criteria
4
• Stable LVAD candidates not using 30 day discretionary period• Inotropes without hemodynamic monitoring• Diagnosis of congenital heart disease (CHD) • Diagnosis of ischemic heart disease with intractable angina• Diagnosis of hypertrophic cardiomyopathy• Diagnosis of restrictive cardiomyopathy• Diagnosis of amyloidosis• Retransplant
5 Combined organ transplants
6 All remaining active candidates
© 2016 AST
Problem
• DSA boundaries create inequities in access to transplant, particularly for the most urgent candidates
Goal
• Increase the number of donors available to the most critically ill patients, without increasing the number of discarded organs
Status
• TSAM request submitted for 4 different allocations sequences
Geographic Sharing Background
15
© 2016 AST
Where Would You Want to Be Waiting As Status I?
(1). 68% > 6 Mos
(2). 67% > 6 Mos
(10). 14%> 6 Mos
(5). 12% > 6 Mos
% of pts listed as Status I
who have been waiting > 6 Months
(6). 52% > 6 Mos
UNOS Data as of April 12, 2013
© 2016 AST
Broader Sharing For Tier 1
Tier 1
DSA
Zone A
Zone B
Zone C
Zone D
Zone E
Offer 1 (All tier 1s in DSA + Zone A + Zone B)
Offer 1 (All tier 1s in DSA + Zone A + Zone B)
DSA
Zone A
Zone B
Zone C
Zone D
Zone E
Offer 2 (All Tier 2s in DSA + Zone A)
Offer 2 (All Tier 2s in DSA + Zone A)
Offer 3 (All Tier 3s in DSA + Zone A)
Offer 3 (All Tier 3s in DSA + Zone A)
Tier
3
DSA
Zone A
Zone B
Zone C
Zone D
Zone E
Tier
2
© 2016 AST
Two Preferred Modeled Sequences
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Broader sharing 1/2A
Candidate status Location
Status 1 adult + Status 1A ped DSA + Zone A
Status 1 adult + Status 1A ped Zone B
Status 2 adult DSA + Zone A
Status 2 adult Zone B
Status 3 adult + Status 1B ped DSA
Status 4 adult DSA
Status 3 adult + Status 1B ped Zone A
Broader sharing 1/2B
Candidate status Location
Status 1 adult + Status 1A ped DSA + Zone A
Status 1 adult + Status 1A ped Zone B
Status 2 adult DSA + Zone A
Status 2 adult Zone B
Status 3 adult + Status 1B ped DSA
Status 3 adult + Status 1B ped Zone A
Status 4 adult DSA
SRTR Data, 2/2014
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Duke Heart Center
Two-year post-transplant mortality rates by simulation
SRTR Data, 2/2014
© 2016 AST
Conclusions
• Multi-tiered system serves to address the problems noted in the current system
– Reduce waiting list mortality rates – allocate organs to the most critically ill candidates
– Addresses issues with specific patients groups, some possibly disenfranchised in today’s allocation system
– Incorporates broader geographic sharing to optimize access and limit regional disparities that may exist
• Post-transplant survival - within each status, projected to remain comparable to those rates in the current system
© 2016 AST
Duke Heart Center
Multi-Organ Transplantation
Am J Transplant 2009;9:844-52
Heart-LungHeart + Abdominal Organ(s)
© 2016 AST
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Problems with the Current System
1. Status 1A candidates are 3x more likely to die on the waiting list than candidates in any other status
2. High # of exception requests indicates certain candidates not served well by current system
3. Policy out of date re: increased use of MCSDs and associated complications
4. Current geographic sharing scheme is inequitable and inconsistent with the Final Rule
© 2016 AST
Medical Urgency
Geography
Combine DSA with
other Zones?
DSA first?
Combine Tiers
Tier by Tier
Who gets the first offer?
© 2016 AST
Proposed New Statuses
28
Current Status
Proposed Status
1A 1
2
3
1B 4
2 5
6
• Proposed statuses 1-3 are generally defined by current status 1A criteria
• Proposed status 4 is generally defined by current status 1B criteria
• Proposed status 5-6 are generally defined by current status 2 criteria